2.5 year old is an early waking nightmare! Advice, experiences and support please!

I didn't realise there was a sleep section and I accidentally posted this in the behaviour/ development section, so please forgive the repeat post here.

Anyway, Hello and Happy New Year. Our DS just turned 2.5 and has been waking up really distressed and screaming every morning like clock work between 4 and 4:30am. He has always been an early waker and historically wakes up around 5-5:30, however about a month ago he started waking up even earlier sometimes before 4am. The early time is definitely awful, but the blood cuddling screaming, physical flailing and inconsolable crying is not only incredibly difficult to deal with at 4am but a complete mystery to us as well.

When he wakes up, he starts crying from the get go, once we walk into the room he immediately screams "get up!" over and over again. If by chance it's my morning and I'm the one to go in he completely loses it and starts screaming "I want my Mommy!" as well. This will sometimes go on for 30 mins before he starts to calm down a enough to get a word in and find some common ground. I have to say that I am extremely proud of my wife and I, because as intense and exhausting as it can get we both have managed to always stay super calm and patient with him. We're both crying tears of exhaustion inside though.

We have tried cry it out, but the level of his distress is so high that it doesn't feel right. We have tried earlier bed times and later bed times. We've tried total dark and a very dim nightlight when he started to ask us not to turn the light out. The one thing that is glaringly obvious is that he is absolutely exhausted as well. He's getting 9 hours at best when he should be getting 12. Historically he's always been a 10 hour baby though.

The only other thought is re: possible ADHD. Both of us have a formal diagnosis of ADHD/ADD and we figured that there would be a good chance that our child may be predisposed to this as well. We have an appointment with the GP and mental health doctor to discuss the possibility.

We have done a lot of internet searching re: early waking and it seems that there is not a lot to do about it and everyone swears that it will pass eventually. I certainly hope so, because at the moment we are losing our minds.

DS. He has always been a terrible sleeper from the moment we brought him home from the hospital. When he was tiny is was due directly to severe reflux which took a million years to get sorted. That seems to have sorted itself out and there is no sign of it anymore.

On the brighter side, once he is up and awake he is a completely happy, sweet, funny and normal toddler. He incredibly fun to be with and makes us laugh all the time. It's just between the hours of 4am - 6am that it all turns into a horror show. We are both chronically under slept for over two years now and it's particularly hard right now.

If anyone has any similar experiences, advice, suggestions etc etc, they would be very much appreciated. Also child rearing is meant for the young, at 47 years old my bootstraps are getting pretty worn out from pulling them up. I will survive!!